From: Eric Dumazet <eric.dumazet@gmail.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: David Miller <davem@davemloft.net>,
netdev@vger.kernel.org, "Serge E. Hallyn" <serge@hallyn.com>
Subject: Re: [PATCH net-next] scm: Don't use struct ucred in NETLINK_CB and struct scm_cookie.
Date: Fri, 07 Sep 2012 17:07:26 +0200 [thread overview]
Message-ID: <1347030446.2484.771.camel@edumazet-glaptop> (raw)
In-Reply-To: <87haralb0u.fsf@xmission.com>
On Thu, 2012-09-06 at 21:20 -0700, Eric W. Biederman wrote:
> Passing uids and gids on NETLINK_CB from a process in one user
> namespace to a process in another user namespace can result in the
> wrong uid or gid being presented to userspace. Avoid that problem by
> passing kuids and kgids instead.
>
> - define struct scm_creds for use in scm_cookie and netlink_skb_parms
> that holds uid and gid information in kuid_t and kgid_t.
>
> - Modify scm_set_cred to fill out scm_creds by heand instead of using
> cred_to_ucred to fill out struct ucred. This conversion ensures
> userspace does not get incorrect uid or gid values to look at.
>
> - Modify scm_recv to convert from struct scm_creds to struct ucred
> before copying credential values to userspace.
>
> - Modify __scm_send to populate struct scm_creds on in the scm_cookie,
> instead of just copying struct ucred from userspace.
>
> - Modify netlink_sendmsg to copy scm_creds instead of struct ucred
> into the NETLINK_CB.
>
> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
> diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
> index 7cb7867..6473267 100644
> --- a/net/netlink/af_netlink.c
> +++ b/net/netlink/af_netlink.c
> @@ -1398,7 +1398,7 @@ static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
>
> NETLINK_CB(skb).pid = nlk->pid;
> NETLINK_CB(skb).dst_group = dst_group;
> - memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
> + NETLINK_CB(skb).creds = siocb->scm->creds;
>
> err = -EFAULT;
> if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
Seems fine to me, but I am not sure why you kept NETLINK_CREDS()
defined/used once.
next prev parent reply other threads:[~2012-09-07 15:07 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-07 4:20 [PATCH net-next] scm: Don't use struct ucred in NETLINK_CB and struct scm_cookie Eric W. Biederman
2012-09-07 15:07 ` Eric Dumazet [this message]
2012-09-07 18:41 ` David Miller
2012-09-07 21:25 ` Eric W. Biederman
2012-09-07 21:32 ` David Miller
2012-09-07 18:42 ` David Miller
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1347030446.2484.771.camel@edumazet-glaptop \
--to=eric.dumazet@gmail.com \
--cc=davem@davemloft.net \
--cc=ebiederm@xmission.com \
--cc=netdev@vger.kernel.org \
--cc=serge@hallyn.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox